Vehicle seats

This application claims priority to Japanese patent application serial number 2007-102619, the contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to vehicle seats. More particularly, the present invention relates to vehicle seats each having a seat cushion.

A vehicle seat having a seat cushion with a side support function is already known. The side support function of the seat cushion may increase restraint performance of a passenger sitting on the seat. In the vehicle seat, the seat cushion is provided with raised (upwardly projected) side support portions, so that femoral portions of the passenger can be laterally supported thereby. The side support portions are respectively disposed in side peripheries of the seat cushion. The side support portions are arranged and constructed to be respectively vertically moved, so that travel distances of the side support portions can be changed. As a result, the restraint performance of the femoral portions of the passenger can be changed. Such a vehicle seat is taught, for example, by Japanese Laid-Open Patent Publication Number 62-56447.

Conversely, a vehicle seat having a seat back with a side support function is already known. In the vehicle seat, the seat back is provided with raised (forwardly projected) side support portions, so that body side portions of the passenger can be laterally supported thereby. The side support portions are respectively disposed in side peripheries of the seat back. The side support portions are arranged and constructed to be respectively moved back and forth, so that travel distances of the side support portions can be changed. As a result, the restraint performance of the body side portions of the passenger can be changed. Further, one of the side support portions is arranged and constructed to be manually moved to a retracted position, so that the side support portion cannot interfere with the passenger when the passenger gets in and out of the vehicle seat. Such a vehicle seat is taught, for example, by Japanese Laid-Open Patent Publication Number 61-37544.

BRIEF SUMMARY OF THE INVENTION

However, the known vehicle seat still are in need of improvement. That is, there is a need in the art for an improved vehicle seat.

For example, in one aspect of the present invention, a vehicle seat may include a seat cushion that includes a central portion, first and second side support portions, and a vertical moving mechanism. The first and second side support portions are capable of laterally supporting femoral portions of a passenger. The vertical moving mechanism is capable of vertically moving the first and second side support portions in synchronism with each other, so as to change heights of the first and second side support portions relative to the central portion. The vertical moving mechanism is arranged and constructed to vertically move each of the first and second side support portions within a use range thereof in which each of the first and second side support portions has side support function. The vertical moving mechanism is arranged and constructed to further vertically move the second side support portion downwardly beyond the use range to a release position in which the second side support portion does not have the side support function.

According to the vehicle seat thus constructed, the heights of the first and second side support portions relative to the seat cushion central portion can be freely changed. Therefore, restraint performance of the femoral portions of the passenger can be controlled for body size of the passenger. In addition, the first and second side support portions can be vertically moved in synchronism with each other. Therefore, the heights thereof can be simultaneously changed. Moreover, the second side support portion can be moved downwardly beyond the use range to the release position. Therefore, the passenger can smoothly get in and out of the vehicle seat.

In one embodiment, the vertical moving mechanism may include first and second drive mechanisms that are respectively linked to the first and second side support portions. The first drive mechanism may include a drive force absorption mechanism that can prevent a drive force from transmitting to the first side support portion when the first side support portion reaches a lowermost use position.

According to this embodiment, when the first side support portion reaches the lowermost use position, the first drive mechanism can be idly driven due to the drive force absorption mechanism. Thus, the drive force can be effectively prevented from transmitting to the first side support portion.

In another embodiment, the first drive mechanism may preferably include a first member having an elongated slot and a second member having a pin. The pin slidably engages the elongated slot, thereby forming the drive force absorption mechanism that can absorb the drive force.

Other objects, features and advantages of the present invention will be readily understood after reading the following detailed description together with the accompanying drawings and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

<figref idrefs="DRAWINGS">FIG. 1</figref> is a perspective view of a vehicle seat according to a first representative embodiment of the present invention;

<figref idrefs="DRAWINGS">FIG. 2</figref> is a cross-sectional view taken along line II-II in <figref idrefs="DRAWINGS">FIG. 1</figref>, which illustrates motion of first and second side support portions of a seat cushion;

<figref idrefs="DRAWINGS">FIG. 3</figref> is a plan view of the seat cushion, which illustrates a framework or inner structure thereof;

<figref idrefs="DRAWINGS">FIG. 4</figref> is a perspective view of the seat cushion, which illustrates the framework or inner structure thereof;

<figref idrefs="DRAWINGS">FIG. 5</figref> is a schematic side view of a second drive mechanism corresponding to the second side support portion that is adjacent to a vehicle door opening;

<figref idrefs="DRAWINGS">FIG. 6</figref> is a schematic side view of a first drive mechanism corresponding to the first side support portion that is spaced away from the vehicle door opening; and

<figref idrefs="DRAWINGS">FIG. 7</figref> is a view similar to <figref idrefs="DRAWINGS">FIG. 6</figref> in a vehicle seat according to a second representative embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Representative examples of the present invention have been described in detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present invention and is not intended to limit the scope of the invention. Only the claims define the scope of the claimed invention. Therefore, combinations of features and steps disclosed in the foregoing detail description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe detailed representative examples of the invention. Moreover, the various features taught in this specification may be combined in ways that are not specifically enumerated in order to obtain additional useful embodiments of the present invention.

Detailed representative embodiments of the present invention are shown in <figref idrefs="DRAWINGS">FIG. 1</figref> to <figref idrefs="DRAWINGS">FIG. 7</figref>.

First Detailed Representative Embodiment

A first detailed representative embodiment of the present invention will be described with reference to <figref idrefs="DRAWINGS">FIGS. 1 to 6</figref>.

As shown in <figref idrefs="DRAWINGS">FIG. 1</figref>, a representative vehicle seat <b>1</b> may preferably be arranged as a rear left seat of a vehicle and include a seat back <b>2</b> having a head rest <b>4</b> and a seat cushion <b>3</b>.

The seat cushion <b>3</b> is composed of a central portion <b>3</b>C and a pair of (right and left or first and second) side support portions <b>3</b>R and <b>3</b>L. The side support portions <b>3</b>R and <b>3</b>L are respectively positioned at an inner (right) side that is spaced away from a vehicle door opening (not shown) and an outer (left) side that is adjacent to the vehicle door opening. The side support portions <b>3</b>R and <b>3</b>L are respectively arranged and constructed to laterally support femoral portions of a passenger P. The side support portions <b>3</b>R and <b>3</b>L are respectively vertically movably disposed in side peripheries of the seat cushion central portion <b>3</b>C. The side support portions <b>3</b>R and <b>3</b>L thus positioned are respectively connected to a vertical moving mechanism <b>10</b>. As shown in <figref idrefs="DRAWINGS">FIG. 2</figref>, the vertical moving mechanism <b>10</b> is arranged and constructed to change lateral (rightward and leftward) tilting angles of the side support portions <b>3</b>R and <b>3</b>L relative to the seat cushion central portion <b>3</b>C, thereby vertically moving the side support portions <b>3</b>R and <b>3</b>L relative to the central portion <b>3</b>C. As a result, distances or heights of the side support portions <b>3</b>R and <b>3</b>L relative to the central portion <b>3</b>C may preferably be changed.

The vertical moving mechanism <b>10</b> may preferably include a vertical moving device <b>20</b>. The vertical moving device <b>20</b> has a motor <b>21</b>, a pair of (first and second) drive mechanisms DR and DL that are coupled to drive shafts <b>22</b> of the motor <b>21</b> via couplers <b>23</b> (<figref idrefs="DRAWINGS">FIG. 3</figref>). As shown in <figref idrefs="DRAWINGS">FIG. 2</figref>, the vertical moving mechanism <b>10</b> further includes a pair of vertical moving or tilting plates <b>11</b>R and <b>11</b>L that are respectively embedded in cushion pads <b>3</b>P of the side support portions <b>3</b>R and <b>3</b>L. Each of the tilting plates <b>11</b>R and <b>11</b>L is laterally rotatably or tiltably attached to a cushion frame <b>3</b>F via a pair of (front and rear) hinge pins <b>11</b><i>h </i>(<figref idrefs="DRAWINGS">FIG. 4</figref>). Further, the tilting plates <b>11</b>R and <b>11</b>L are respectively movably linked to the drive mechanisms DR and DL of the vertical moving device <b>20</b>, so as to be laterally tilted as indicated by solid and broken lines in <figref idrefs="DRAWINGS">FIG. 2</figref> when the drive motor <b>21</b> is actuated. Therefore, upon actuation of the drive motor <b>21</b>, the side support portions <b>3</b>R and <b>3</b>L can be laterally tilted as indicated by solid and broken lines in <figref idrefs="DRAWINGS">FIG. 2</figref>, so that the heights of the side support portions <b>3</b>R and <b>3</b>L relative to the seat cushion central portion <b>3</b>C can be changed.

Further, the vertical moving mechanism <b>10</b> (the vertical moving device <b>20</b>) is arranged and constructed such that the side support portions <b>3</b>R and <b>3</b>L (the tilting plates <b>11</b>R and <b>11</b>L) can be laterally tilted in substantially synchronism with each other when the drive motor <b>21</b> is actuated.

Thus, restraint performance of the femoral portions of the passenger P can be adjusted for body size of the passenger P because the heights of the side support portions <b>3</b>R and <b>3</b>L relative to the seat cushion central portion <b>3</b>C can be changed.

As best shown in <figref idrefs="DRAWINGS">FIG. 2</figref>, the drive mechanism DL of the vertical moving device <b>20</b> is generally arranged and constructed to tilt the side support portion <b>3</b>L (the tilting plate <b>11</b>L) within a use range thereof in which the side support portion <b>3</b>L substantially has side support function, i.e., between an uppermost use position shown by broken lines and a lowermost use position shown by thin solid lines. Also, the drive mechanism DL is arranged and constructed to further tilt the side support portion <b>3</b>L (the tilting plate <b>11</b>L) downwardly until the side support portion <b>3</b>L reaches a position or condition in which it is substantially flush with the central portion <b>3</b>C of the seat cushion <b>3</b> as shown by bold solid lines. In other words, the drive mechanism DL is arranged and constructed to further tilt the side support portion <b>3</b>L (the tilting plate <b>11</b>L) downwardly beyond the use range until the side support portion <b>3</b>L reaches a (substantially horizontal) position or condition in which it does not substantially have the side support function, which position or condition will be hereinafter referred to as a release position or condition. As will be appreciated, when the side support portion <b>3</b>L is in the release position, the side support portion <b>3</b>L can be effectively prevented from interfering with the passenger P when the passenger P gets in and out of the vehicle seat <b>1</b>. As a result, when the side support portion <b>3</b>L is tilted to such a position, the passenger can smoothly get in and out of the vehicle seat <b>1</b>. Further, the release position or condition can be referred to as a welcome position or condition. In <figref idrefs="DRAWINGS">FIG. 1</figref>, the welcome position of the side support portion <b>3</b>L is indicated by broken lines.

Thus, the heights of the side support portion <b>3</b>L relative to the seat cushion central portion <b>3</b>C can be adjusted by tilting the side support portion <b>3</b>L (the tilting plate <b>11</b>L) within the use range. In addition, the side support portion <b>3</b>L can be shifted to the release condition by further tilting the side support portion <b>3</b>L downwardly beyond the use range.

Similarly, as best shown in <figref idrefs="DRAWINGS">FIG. 2</figref>, the drive mechanism DR of the vertical moving device <b>20</b> is generally arranged and constructed to tilt the side support portion <b>3</b>R (the tilting plate <b>11</b>R) within a use range thereof in which the side support portion <b>3</b>R substantially has side support function, i.e., between an uppermost use position shown by broken lines and a lowermost use position shown by solid lines. However, unlike the drive mechanism DL, the drive mechanism DR is not arranged and constructed to further tilt the side support portion <b>3</b>R (the tilting plate <b>11</b>R) downwardly beyond the use range. That is, the side support portion <b>3</b>R (the tilting plate <b>11</b>R) may preferably be prevented from downwardly tilting beyond the use range (the lowermost use position) by means of a stopper mechanism (not shown).

Thus, the heights of the side support portion <b>3</b>R relative to the seat cushion central portion <b>3</b>C can be adjusted by tilting the side support portion <b>3</b>R (the tilting plate <b>11</b>R) within the use range.

Further, the drive mechanisms DR and DL of the vertical moving device <b>20</b> are respectively arranged and constructed such that the side support portions <b>3</b>R and <b>3</b>L (the tilting plates <b>11</b>R and <b>11</b>L) can be laterally tilted within their use ranges in substantially synchronism with each other. Also, the drive mechanism DL is arranged and constructed to tilt the side support portion <b>3</b>L (the tilting plate <b>11</b>L) to the release (welcome) position beyond the use range thereof independently of the side support portion <b>3</b>R.

Further, the side support portion <b>3</b>L can be automatically tilted toward the release position beyond the use range when a vehicle door (not shown) is opened. That is, when the vehicle door is opened, the vertical moving device <b>20</b> is actuated based on a door opening signal from a sensor (not shown) that is disposed in the vehicle door opening, so that the side support portion <b>3</b>L can be automatically tilted toward the release position beyond the use range. To the contrary, the side support portion <b>3</b>L can be automatically tilted from the release position to the use range when the vehicle door is closed. That is, when the vehicle door is closed, the vertical moving device <b>20</b> is actuated based on a door closing signal from the sensor, so that the side support portion <b>3</b>L can be automatically tilted toward the use range from the release position.

Next, the vertical moving mechanism <b>10</b> will be described in detail.

The motor <b>21</b> of the vertical moving device <b>20</b> is positioned under the seat cushion <b>3</b> and is fixedly connected to a vehicle floor F. The motor <b>21</b> is arranged so as to be actuated by moving an operation lever L (<figref idrefs="DRAWINGS">FIG. 1</figref>) that is attached to an appropriate portion of the vehicle seat <b>1</b>. The lever L may preferably be constructed to turn on and off the motor <b>21</b> or to change rotation of direction (normal or reverse direction) of the motor <b>21</b>. In this embodiment, when the lever L is rotated forwardly, the motor <b>21</b> is rotated in normal direction, so that the side support portions <b>3</b>R and <b>3</b>L (the tilting plates <b>11</b>R and <b>11</b>L) can be rotated or moved downwardly. To the contrary, when the lever L is rotated rearward, the motor <b>21</b> is rotated in the reverse direction, so that the side support portions <b>3</b>R and <b>3</b>L (the tilting plates <b>11</b>R and <b>11</b>L) can be rotated or moved upwardly. Thus, the side support portions <b>3</b>R and <b>3</b>L (the tilting plates <b>11</b>R and <b>11</b>L) can be controllably rotated between the uppermost and lowermost use positions (i.e., within the use range).

Further, when the lever L is released, the motor <b>21</b> is deactuated or stopped, so that rotational motion of the side support portions <b>3</b>R and <b>3</b>L (the tilting plates <b>11</b>R and <b>11</b>L) can be stopped. Thus, the side support portions <b>3</b>R and <b>3</b>L (the tilting plates <b>11</b>R and <b>11</b>L) can be maintained at desired rotational positions.

Further, the motor <b>21</b> is arranged to be actuated based on the door opening or door closing signal from the sensor that is disposed in the vehicle door opening. As will be appreciated, when the door opening signal is transmitted to the motor <b>21</b>, the motor <b>21</b> is rotated in the normal direction, so that the side support portions <b>3</b>R and <b>3</b>L (the tilting plates <b>11</b>R and <b>11</b>L) can be rotated or moved downwardly. To the contrary, when the door closing signal is transmitted to the motor <b>21</b>, the motor <b>21</b> is rotated in the reverse direction, so that the side support portions <b>3</b>R and <b>3</b>L (the tilting plates <b>11</b>R and <b>11</b>L) can be rotated or moved upwardly.

As previously described, each of the tilting plates <b>11</b>R and <b>11</b>L is laterally rotatably or tiltably attached to a cushion frame <b>3</b>F via the front and rear hinge pins <b>11</b><i>h </i>(<figref idrefs="DRAWINGS">FIG. 4</figref>). Further, as described above, the tilting plates <b>11</b>R and <b>11</b>L are respectively movably linked to the drive mechanisms DR and DL of the vertical moving device <b>20</b>. In particular, the drive mechanisms DR and DL respectively include hinge members <b>11</b><i>t</i>, linking members <b>12</b>R and <b>12</b>L, screw rods <b>24</b>R and <b>24</b>L and nuts <b>25</b>R and <b>25</b>L. As best shown in <figref idrefs="DRAWINGS">FIG. 4</figref>, the hinge members <b>11</b><i>t </i>are respectively attached to the tilting plates <b>11</b>R and <b>11</b>L. Further, upper ends of the linking members <b>12</b>R and <b>12</b>L are respectively rotatably connected to the hinge members <b>11</b><i>t </i>via pins <b>12</b><i>a</i>. Conversely, lower ends of the linking members <b>12</b>R and <b>12</b>L are respectively rotatably connected to the nuts <b>25</b>R and <b>25</b>L via pins <b>12</b><i>b </i>that are associated with the nuts <b>25</b>R and <b>25</b>L. The nuts <b>25</b>R and <b>25</b>L respectively threadably engage the screw rods <b>24</b>R and <b>24</b>L, so as to move therealong when the screw rods <b>24</b>R and <b>24</b>L are rotated.

As best shown in <figref idrefs="DRAWINGS">FIG. 3</figref>, the screw rods <b>24</b>R and <b>24</b>L are respectively substantially horizontally positioned at both sides of the seat cushion <b>3</b> so as to longitudinally extend therealong, and are rotatably connected to the vehicle floor F via brackets <b>24</b><i>a</i>. Further, as shown in <figref idrefs="DRAWINGS">FIGS. 3 and 4</figref>, forward ends of the screw rods <b>24</b>R and <b>24</b>L are respectively threadably engage the drive shafts <b>22</b> via the couplers <b>23</b>, so that the screw rods <b>24</b>R and <b>24</b>L can be rotated in synchronism with each other when the motor <b>21</b> is actuated. Each of the couplers <b>23</b> may preferably include, for example, but is not limited to, a worm and worm wheel assembly.

Further, as best shown in <figref idrefs="DRAWINGS">FIG. 6</figref>, the linking member <b>12</b>R (a first member) of the drive mechanism DR has a bent portion that is formed in the lower end thereof. The bent portion of the linking member <b>12</b>R has an elongated slot Rh that is formed therein. The elongated slot Rh may preferably be shaped to be substantially horizontally oriented (i.e., to be substantially parallel to the screw rod <b>24</b>R) when the tilting plate <b>11</b>R (the side support portion <b>3</b>R) is stopped by means of the stopper mechanism (i.e., when the tilting plate <b>11</b>R reaches the lowermost use position thereof shown by solid lines in <figref idrefs="DRAWINGS">FIG. 6</figref>). The pin <b>12</b><i>b </i>associated with the nut <b>25</b>R (a second member) slidably engages the elongated slot Rh, thereby forming an elongated slot-pin connection. Thus, a drive force absorption mechanism is formed in the drive mechanism DR. The drive force absorption mechanism thus constructed can absorb a drive force of the motor <b>21</b>, so as to prevent the drive force from transmitting to the tilting plate <b>11</b>R (the side support portion <b>3</b>R).

In addition, as shown in <figref idrefs="DRAWINGS">FIG. 6</figref>, an extension spring <b>13</b> is provided between the tilting plate <b>11</b>R and the cushion frame <b>3</b>F, so that the tilting plate <b>11</b>R can be normally biased downwardly via a spring force of the extension spring <b>13</b>. As a result, the linking member <b>12</b>R is normally biased such that the lower end thereof is biased rearward (leftward in <figref idrefs="DRAWINGS">FIG. 6</figref>). Therefore, as shown by broken lines in <figref idrefs="DRAWINGS">FIG. 6</figref>, the pin <b>12</b><i>b </i>is normally pressed to a forward end periphery of the elongated slot Rh.

Operation of the vehicle seat <b>1</b> (the vertical moving mechanism <b>10</b>) will now be described.

First, when the vehicle door is opened in order to get in the vehicle seat <b>1</b>, the motor <b>21</b> is rotated in the normal direction based on the door opening signal from the sensor. Upon actuation of the motor <b>21</b>, the screw rods <b>24</b>R and <b>24</b>L of the drive mechanism DR and DL are respectively rotated in normal directions, so that the nuts <b>25</b>R and <b>25</b>L respectively move rearward therealong. As a result, as shown in <figref idrefs="DRAWINGS">FIGS. 5 and 6</figref>, the tilting plates <b>11</b>R and <b>11</b>L are respectively tilted downwardly toward the lowermost use positions thereof via the linking members <b>12</b>R and <b>12</b>L.

When the screw rods <b>24</b>R and <b>24</b>L are further rotated, the nut <b>25</b>L of the drive mechanism DL further moves rearward along the screw rod <b>24</b>L, so that the tilting plate <b>11</b>L can be further tilted downwardly to the release (welcome) position via the linking member <b>12</b>L, which position is shown by solid lines in <figref idrefs="DRAWINGS">FIG. 5</figref>. As a result, the side support portion <b>3</b>L (the tilting plate <b>11</b>L) can be changed to the release position shown by bold solid lines in <figref idrefs="DRAWINGS">FIG. 2</figref>. Therefore, the passenger can smoothly get in the vehicle seat <b>1</b>.

Conversely, the tilting plate <b>11</b>R, when reaches the lowermost use position shown by solid lines in <figref idrefs="DRAWINGS">FIG. 6</figref>, can be prevented from further downwardly tilting by means of the stopper mechanism. Therefore, the side support portion <b>3</b>R (the tilting plate <b>11</b>R) can be maintained at the lowermost use position shown by solid lines in <figref idrefs="DRAWINGS">FIG. 2</figref>.

At this time, similar to the nut <b>25</b>L of the drive mechanism DL, the nut <b>25</b>R of the drive mechanism DR can further move rearwardly along the screw rods <b>24</b>R. However, the nut <b>25</b>R of the drive mechanism DR can move rearwardly along the screw rods <b>24</b>R while sliding the pin <b>12</b><i>b </i>associated with the nut <b>25</b>R along the elongated slot Rh formed in the linking member <b>12</b>R. That is, the nut <b>25</b>R of the drive mechanism DR can move idly rearwardly along the screw rods <b>24</b>R due to the drive force absorption mechanism. Thus, the drive mechanism DR can be driven idly. Therefore, the drive force of the motor <b>21</b> can be effectively absorbed, so as to be prevented from transmitting to the linking member <b>12</b>R via the nut <b>25</b>R. As a result, after the tilting plate <b>11</b>R reaches the lowermost use position, the motor drive force can be prevented from transmitting to the tilting plate <b>11</b>R (the side support portion <b>3</b>R).

When the vehicle door is closed after the passenger P sits the vehicle seat <b>1</b>, the motor <b>21</b> is rotated in the reverse direction based on the door opening signal from the sensor. Upon actuation of the motor <b>21</b>, the screw rods <b>24</b>R and <b>24</b>L are respectively rotated in reverse directions, so that the nut <b>25</b>L moves forward along the screw rod <b>24</b>L. As a result, the tilting plate <b>11</b>L (the side support portion <b>3</b>L) is returned from the release position to the use range thereof via the linking member <b>12</b>L. Thus, both of the side support portions <b>3</b>R and <b>3</b>L (the tilting plates <b>11</b>R and <b>11</b>L) can be positioned in the use ranges thereof, so as to laterally support the femoral portions of the passenger P.

At this time, the nut <b>25</b>R moves forwardly along the screw rods <b>24</b>R while reversely sliding the pin <b>12</b><i>b </i>associated with the nut <b>25</b>R along the elongated slot Rh formed in the linking member <b>12</b>R. That is, the nut <b>25</b>R moves idly forwardly along the screw rods <b>24</b>R. Therefore, the drive force of the motor <b>21</b> can be prevented from transmitting to linking member <b>12</b>R via the nut <b>25</b>R.

In the use ranges of the side support portions <b>3</b>R and <b>3</b>L, the side support portions <b>3</b>R and <b>3</b>L can be rotated or moved upwardly and downwardly by operating the lever L, so that the heights of the side support portions <b>3</b>R and <b>3</b>L relative to the seat cushion central portion <b>3</b>C can be freely changed. Thus, the restraint performance of the femoral portions of the passenger P can be controlled for the body size of the passenger P.

Further, when the vehicle door is opened in order to get out of the vehicle seat <b>1</b>, the side support portion <b>3</b>L (the tilting plate <b>11</b>L) is moved to the release position shown by bold solid lines in <figref idrefs="DRAWINGS">FIG. 2</figref> in the same manner as described above. Therefore, the passenger can smoothly get out of the vehicle seat <b>1</b>.

According to the vehicle seat <b>1</b> of the present embodiment, the side support portions <b>3</b>R and <b>3</b>L can be freely vertically moved within the use ranges thereof. Therefore, it is possible to change the restraint performance of the femoral portions of the passenger P. In addition, the side support portion <b>3</b>L can be moved to the release position in which it is substantially flush with the central portion <b>3</b>C of the seat cushion <b>3</b>. Therefore, the side support portion <b>3</b>L cannot interfere with the passenger P when the passenger P gets in and out of the vehicle seat <b>1</b>.

Further, the drive force absorption mechanism of the drive mechanism DR is simply composed of the elongated slot Rh formed in the linking member <b>12</b>R and the pins <b>12</b><i>b </i>associated with the nut <b>25</b>R. Therefore, the drive force absorption mechanism may have a simple structure.

Second Detailed Representative Embodiment

The second detailed representative embodiment will now described in detail with reference to <figref idrefs="DRAWINGS">FIG. 7</figref>.

Because the second embodiment relates to the first embodiment, only the constructions and elements that are different from the first embodiment will be explained in detail. Elements that are the same in the first and second embodiments will be identified by the same reference numerals and a detailed description of such elements may be omitted.

In this embodiment, in place of the elongated slot Rh that is formed in the bent portion of the linking member <b>12</b>R, an elongated slot Th may preferably be formed in the hinge member <b>11</b><i>t </i>(the first member) that is attached to the tilting plate <b>11</b>R. The elongated slot Th may preferably be shaped to be substantially horizontally oriented (i.e., to be substantially parallel to the screw rod <b>24</b>R).

The pin <b>12</b><i>a </i>associated with the linking member <b>12</b>R (the second member) slidably engages the elongated slot Th formed in the hinge member <b>11</b><i>t</i>, thereby forming the elongated slot-pin connection. Thus, similar to the first embodiment, the drive force absorption mechanism is formed in the drive mechanism DR. Further, as shown by broken lines in <figref idrefs="DRAWINGS">FIG. 7</figref>, the pin <b>12</b><i>a </i>is normally pressed to forward end periphery of the elongated slot Th via the spring force of the extension spring <b>13</b>.

According to the vehicle seat <b>1</b> of the second embodiment, after the tilting plate <b>11</b>R reaches the lowermost use position shown by solid lines in <figref idrefs="DRAWINGS">FIG. 7</figref>, the nut <b>25</b>R of the drive mechanism DR can further move rearwardly along the screw rods <b>24</b>R with the linking member <b>12</b>R while sliding the pin <b>12</b><i>a </i>associated with the linking member <b>12</b>R along the elongated slot Th formed in the hinge member <b>11</b><i>t</i>. That is, the nut <b>25</b>R can move idly rearwardly along the screw rods <b>24</b>R due to the drive force absorption mechanism. Thus, similar to the first embodiment, the drive mechanism DR can be driven idly. Therefore, the drive force of the motor <b>21</b> can be absorbed, so as to be prevented from transmitting to the linking member <b>12</b>R via the nut <b>25</b>R. As a result, similar to the first embodiment, after the tilting plate <b>11</b>R reaches the lowermost use position, the motor drive force can be prevented from transmitting to the tilting plate <b>11</b>R (the side support portion <b>3</b>R).

Naturally, various changes and modifications may be made to the present invention without departing from the scope of the invention. For example, in the embodiments, the tilting plate <b>11</b>L (the side support portion <b>3</b>L) is constructed to be tilted to the position in which it is substantially flush with the central portion <b>3</b>C of the seat cushion <b>3</b>. However, the tilting plate <b>11</b>R (the side support portion <b>3</b>R) can instead be constructed to be tilted to a position in which it is substantially flush with the central portion <b>3</b>C of the seat cushion <b>3</b>, if necessary.